It is known in the proton exchange membrane fuel cell art to evaporatively cool fuel cells, thereby deriving the benefit of the heat of vaporization, in contrast with conveying sensible heat to circulating water passing through the cells or coolant passing through coolant plates. One example is shown in U.S. Pat. No. 7,504,170, which is incorporated herein by reference.
In some applications, such as in vehicles, extremely high current densities are preferred in order to support high vehicle performance. High current densities increase water production, which requires assured flow through porous, hydrophilic reactant gas flow field plates, hereafter also referred to as “water transport plates”. Furthermore, increased power density requires assured cooling and humidification of the membrane.
For high performance, the very best communication of water between water passageways and the water transport plates is beneficial.